Nights stay kind in San Antonio Heights each January, milder than in 94% of U.S. towns
Expect July afternoons of about 92°. It is a dry place: less rain and snow fall here than on 89% of U.S. towns. Compared with 1901–2000, the average now sits 2.5° higher. For walks and days out, the stretch from October to May brings highs of 65–81°.
A year in San Antonio Heights at a glance
Each month’s typical high and low, and what it brings.
What stands out about San Antonio Heights’ climate
Compared with towns across the U.S., with San Antonio Heights’ place in California beside it.
What a year in San Antonio Heights feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
Frost is rare
Frost dates and degree days from Ontario International Airport, 8 miles away.
The 2023 USDA map puts San Antonio Heights’ center in zone 10a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 32°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 20 inches of rain a year
February is the wettest month and August the driest. Rain falls on about 42 days a year. Snow is rare: about 0.0" in a normal year at Glendora Fc 287b, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in San Antonio Heights
40% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55° run from December.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Ontario International Airport.
Living with San Antonio Heights’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10a. Frost comes about 1 winter in 2, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, May, October, November and December. 4.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in San Antonio Heights from natural hazards, river flooding is the largest share (49%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →San Antonio Heights and its neighbors
Upland has the coldest January nights next door (44°, 2° colder). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like San Antonio Heights’, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| San Antonio Heights, CA | 46° | 92° | 20" | 0.0" |
| Port Isabel, TX | 52° | 92° | 26" | 0.2" |
| Corona de Tucson, AZ | 36° | 96° | 14" | 0.1" |
| Eagle Point, OR | 32° | 92° | 23" | 3.4" |
| Santa Teresa, NM | 33° | 95° | 9" | 2.0" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in San Antonio Heights averaged 2.5° warmer than the 1900s. The biggest change is in January (+3.5°).
A bigger shift than in all but 60 U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How San Antonio Heights compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with San Antonio Heights’ place among California’s.
San Antonio Heights weather by month
Highs, lows and precipitation from NOAA’s grid at San Antonio Heights’ center; snow, wet days and snow on the ground from Glendora Fc 287b, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 65° | 46° | 4.5" | 0.0" | 7 | 0 | 52° – 62° |
| February | 66° | 46° | 5.1" | 0.0" | 7 | 0 | 48° – 65° |
| March | 69° | 46° | 3.3" | 0.0" | 6 | 0 | 51° – 65° |
| April | 73° | 49° | 1.1" | 0.0" | 4 | 0 | 55° – 65° |
| May | 78° | 53° | 0.6" | 0.0" | 3 | 0 | 59° – 73° |
| June | 85° | 58° | 0.1" | 0.0" | 2 | 0 | 66° – 77° |
| July | 92° | 64° | 0.1" | 0.0" | 1 | 0 | 72° – 83° |
| August | 94° | 65° | 0.0" | 0.0" | 0 | 0 | 76° – 83° |
| September | 90° | 64° | 0.1" | 0.0" | 1 | 0 | 72° – 81° |
| October | 81° | 57° | 0.9" | 0.0" | 3 | 0 | 64° – 74° |
| November | 72° | 50° | 1.3" | 0.0" | 3 | 0 | 53° – 66° |
| December | 65° | 44° | 3.3" | 0.0" | 6 | 0 | 50° – 61° |
| Year | 77° | 53° | 20.4" | 0.0" | 42 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 48° to 65°. August is the most reliable, staying within 7°.
Where San Antonio Heights’ numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at San Antonio Heights’ center.
- Snow: Glendora Fc 287b, CA.
- Frost dates, heating and cooling: Ontario International Airport, 8 miles away.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about San Antonio Heights’ climate
What is the weather like in San Antonio Heights?
A typical July afternoon reaches 92°, a January night drops to 46°, and snow is almost unheard of. Milder January nights than 94% of U.S. towns; hotter July afternoons than 88% of U.S. towns.
How cold does it get in San Antonio Heights in winter?
December nights average 44°. About 2 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 50°.
How much snow does San Antonio Heights get?
About 0.0 inches in a normal winter at Glendora Fc 287b, CA, so most winters see none.
How hot does it get in San Antonio Heights?
July, with a typical high of 92° and a low of 64°. About 93 days a year reach 90° (Ontario International Airport).
When is the first and last frost in San Antonio Heights?
Most years have no frost at all: a 32° night comes in about 41% of winters at Ontario International Airport, usually in December or January.
What growing zone is San Antonio Heights in?
Zone 10a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 32°.
What is the best time of year to visit San Antonio Heights?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is San Antonio Heights getting warmer?
Yes: 1991–2020 averaged 2.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than all but 60 U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in San Antonio Heights.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.